The present invention relates in general to latches for cases and containers where a lid member is secured to a tray portion by means of one latch or a plurality of latches. More specifically, the present invention relates to a single-action latch for a medical case where the latch can be opened and closed by the use of only one finger. Further, the opening and closing motion is continuous and singular in nature.
At the present time there are a variety of cases which are used for the storage and transport of equipment, instruments, and supplies and which include a tray portion and a closing lid member. While the lid member may be hinged along one edge to the tray portion, the lid member may also be separate and not attached to the tray portion. Regardless of the specific lid configuration, at least one side of the lid member must lift or pivot away from the tray portion in order for the end user to gain access to the interior storage area of the tray portion. Accordingly, it is desired to be able to secure this one side in a closed condition against a corresponding side or edge of the tray portion. When the lid is completely separate from the tray portion, a pair of latches, oppositely disposed, are normally used to secure the lid to the tray portion. A common means of securing the lid member and tray portion together is to use a multi-component latch with a particular operating linkage. Typically one portion of the latch is anchored to the outer wall of the tray portion and a cooperating clamp portion of the latch extends up and over the outer peripheral edge of the lid member. Through the arrangement and interaction of various linkage members, the clamp portion is able to assume a free state so that it can be oriented over the edge of the lid member and then moved into a locked orientation.
One example of what has been only generally described is provided by U.S. Pat. No. 4,915,913 which issued Apr. 10, 1993 to Williams et al. Another example is provided by U.S. Pat. No. 2,893,771 which issued Jul. 7, 1959 to Claude-Mantle.
When a latch is being designed for a medical case, there are certain considerations which need to be factored into the latch configuration. Some of these considerations include the aesthetics of the design, the size, acceptable materials, and the absence of sharp corners or edges. Other considerations should include the specific method of use, the relative ease or difficulty in opening and closing the medical case, how secure is the latch, and whether there are any loose or free moving components parts.
While different customers and end users may prioritize these various considerations differently, the method of use and the relative ease or difficulty in manipulating the latch are believed to be near the top of every list. When the latch is to be used for a medical case, it is important to have a latch which is free of sharp corners or edges which might cut or puncture surgical gloves. If dangling or freely moving component parts can be avoided, there will be less noise and less risk of something catching on the component part. In turn, this then reduces the risk of the case being jarred or spilled. While it is important to have a secure clamping action of the lid member onto the tray portion, it is equally important to be able to easily release the latch.
The present invention addresses each of these design considerations in a novel and unobvious way. The resultant latch according to a typical embodiment of the present invention has an aesthetically pleasing configuration, no sharp corners or edges, no freely moving or dangling components parts, and the overall configuration is easy to use and convenient. A unique linkage arrangement is provided which enables the latch to be closed by a single action which can be manipulated by one finger. In the closed condition, there is an over-the-center arrangement which provides a snap-lock feature. While the latch is very secure and reliably holds the lid member onto the tray portion due to this particular design, the latch can be manually released with a single action by the use of one finger. However, the over-the-center snap-lock feature prevents the latch from coming unhooked due simply to transport and handling movement and vibrations.
While single-action latch movement may have been employed in earlier latch designs, the specific style and configuration of the present invention is still believed to be novel an unobvious. For example, U.S. Pat. No. 2,744,778 which issued May 8, 1956 to Cooke, discloses a latch-type of device which seems to have a single-action manner of closing, based on the FIG. 4 illustration. However, as can be seen, this design is significantly different from the present invention and includes a number of the previously suggested disadvantages or drawbacks when designing a latch for a medical case.